private void btnCheckAllMClients_Click(object sender, EventArgs e)
        {
            int ClientGroupID = 0;

            if (dgvMClientsGroups.SelectedRows.Count > 0)
            {
                ClientGroupID = Convert.ToInt32(dgvMClientsGroups.SelectedRows[0].Cells["ClientGroupID"].Value);
            }
            OrdersManager.CheckMClients(true, ClientGroupID);
            OrdersManager.CheckMClientGroups(true, ClientGroupID);
        }